Lazarus Pascal Requires Chilkat v11.7.0+

Clipped, Off-Page and White-on-White Text in PDF Extraction

See more PDF Text Extraction Examples

Demonstrates the "clippedText", "offPageText" and "obscuredText" filters. Text that a reader never sees - hidden by a clipping path, outside the crop box, or drawn in the same color as the box beneath it - is excluded by default, and the quality report notes what was skipped. Each kind can be included. Lazarus Pascal

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Pdf,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  pdf: TPdf;
  json: TJsonObject;
  jsonOut: TJsonObject;
  i: Integer;
  count_i: Integer;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  //  The PDF used in this example is available at hidden_text.pdf

  pdf := TPdf.Create;
  success := pdf.LoadFile('qa_data/pdf/hidden_text.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  json := TJsonObject.Create;
  jsonOut := TJsonObject.Create;

  //  The page has a visible paragraph plus three hidden lines: one drawn outside its clipping
  //  rectangle, one below the crop box, and one in white on a white box.
  success := pdf.ExtractText('text',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;
  WriteLn('---- default ----');
  WriteLn(jsonOut.StringOf('text'));

  //  The quality report says what was left out.
  i := 0;
  count_i := jsonOut.SizeOfArray('quality.pages[0].issues');
  while i < count_i do
    begin
      jsonOut.I := i;
      WriteLn('issue: ' + jsonOut.StringOf('quality.pages[0].issues[i].code'));
      i := i + 1;
    end;

  //  Include everything.
  json.UpdateString('clippedText','include');
  json.UpdateString('offPageText','include');
  json.UpdateString('obscuredText','include');
  success := pdf.ExtractText('text',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;
  WriteLn('---- clippedText, offPageText, obscuredText: include ----');
  WriteLn(jsonOut.StringOf('text'));

  //  Sample output:

  //  ---- default ----
  //  Visible Text
  //  
  //  This paragraph is visible. The page also carries three kinds of text a reader never sees.
  //  
  //  End of the visible text.
  //  issue: obscuredTextSkipped
  //  issue: clippedTextSkipped
  //  ---- clippedText, offPageText, obscuredText: include ----
  //  Visible Text
  //  
  //  This paragraph is visible. The page also carries three kinds of text a reader never sees.
  //  
  //  CLIPPED: this line is drawn outside its clipping rectangle.
  //  
  //  OBSCURED: this line is white on a white box.
  //  
  //  End of the visible text.
  //  
  //  OFFPAGE: this line sits below the crop box.


  pdf.Free;
  json.Free;
  jsonOut.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.